Lithium therapy and suicide risk.

BACKGROUND

Studies from the early 90s have suggested that patients selected for and compliant with treatment at specialized lithium clinics have lower-than-expected suicide rates. The present study examines whether such findings can be replicated under less select treatment conditions.

METHOD

All 362 patients in Göteborg, Sweden, with DSM-III-R mood or schizoaffective disorders, hospitalized at least once during an 8-year period and treated with lithium for a minimum of 1 year, were followed. The study included 3911 patient-years on lithium and, because of permanent or temporary discontinuation, 1274 patient-years off lithium.

RESULTS

The risk of suicide was significantly increased on (standard mortality ratio [SMR] = 6.1) as well as off lithium (SMR = 29.0), but the relative risk of suicide was 4.8 times higher during periods off lithium (p < .02; 95% confidence limits 1.1 to 12.6). Ongoing lithium treatment was associated with a 77% reduction in the risk of suicide, whereas alcohol or drug abuse was associated with a 284% increased risk.

CONCLUSION

The findings suggest that ongoing lithium treatment is associated with a lower suicide risk. Whether this is due to lithium's mood-stabilizing properties, to lower suicide risk per se in the patients who remain in treatment, or to a specific antisuicidal effect of the lithium ion cannot be determined since patients were not randomized to discontinue treatment. This methodological shortcoming is shared with every study in the field. All results regarding the influence of lithium on suicide rates must therefore be interpreted with extreme caution.